Field of the Invention
The present invention relates to a junk catching device.
Description of the Related Art Including Information Disclosed 37 CFR 1.97 and 1.98
During some types of working operations in the well, there is a risk that junk, such as debris, metal fragments, metal parts or other unwanted objects will travel (i.e. fall or sink) down into the well. A junk catching device is a tool used in oil and/or gas wells for catching such junk and thereby preventing it from traveling further down into the well.
The unwanted objects are often also referred to as “fish”, as such objects must be fished or picked up from the well before other types of operations can be performed. If not, these objects may present obstructions which may prevent well tools from passing their location in the well.
A junk catching device may also be provided above plugging devices, such as bridge plugs, straddle packers etc in order to prevent drilling fluid to enter the annular space between the plugging devices and the inner surface of the well pipe. Such well fluid tend to precipitate solid matter over time, and if the solid matter reaches anchoring devices or supporting devices for sealing elements of plugging devices, then such plugging devices may be difficult to retrieve from the well. Such situations may occur of it is necessary to interrupt an offshore oil/gas well due to bad weather conditions, where it may take several weeks to continue the well operation.
U.S. Pat. No. 3,107,742 describes an apparatus for recovery of drill cuttings from subsurface earth formations. It comprises a guiding device for guiding junk into a junk container. The guiding device is made of a plurality of elongated spring wires.
GB 2170837 A describes a junk sub comprising a membrane extending from a lip into the annulus. A movable cover may be used to protect the membrane during drilling or circulation.
U.S. Pat. No. 2,927,644 A describes a junk basket with a rubber cup for guiding junk into the junk basket.
U.S. Pat. No. 2,300,438 discloses a retrievable well packer comprising a neoprene cup 39 to catch sediments from falling into the well.
The objects of the invention is to provide a junk catching device which can be set in a well, which is able to prevent junk from passing the device (i.e. it has a high catch rate) and which can be retrieved from the well after use.